Drill pipe handling systems are used in conjunction with hydrocarbon drilling or workover rigs (hereinafter just drilling rigs). Pipe pickup takes place when pipe at or near ground level is picked up and provided to the drilling rig. Conversely, pipe lay down takes place when pipe removed from the borehole needs to be removed from the drilling rig, such as when drilling operations are complete.
Pipe handling operations using wireline systems involve selective control of cables to which a pipe cradle is attached. For pipe pick up operations, pipe sections are picked up by the pipe cradle from a pipe rack. By controlling tension of a first cable, the elevation of the pipe cradle is changed, and by controlling tension of a second cable the horizontal position of the pipe cradle is changed. By selectively controlling the cables the pipe cradle is positioned proximate to the floor of a drilling rig, where the drilling rig's hoist jack picks up the pipe. By removing tension on the cables, and by operation of the force of gravity, the pipe cradle moves away from the drilling rig and lowers in elevation for pickup of another pipe section. For pipe lay down operations, the process is reversed, with cable tension moving the pipe cradle toward the drilling rig where a pipe is placed in the pipe cradle, and gravity forcing the pipe cradle and pipe section toward the pipe rack. Because the pipe cradle is suspended from above, pipe pickup and lay down operations are limited to one side of the pipe cradle. Moreover, when the floor of the drilling rig is close to ground level (e.g., ten feet or less), wireline system operation suffers because of the reliance on the force of gravity to return the cradle to the pipe rack elevation.
Pipe handling operations using catwalk systems involve use of a pipe lifting system that lifts pipe from the pipe rack near ground level and places the pipe on a horizontal catwalk situated at the elevation of the floor of the drill rig. Use of catwalk system is limited to drilling rigs whose floors are relatively close to the ground. For example, catwalk systems are not viable for pipe handling where the floor of the drilling rigs is relatively high (e.g., approximately 15 feet or more).
Thus, demand persists for improved pipe handling equipment and methods that are safer, more efficient and have broader application to varying drilling rig configurations.